Scientific name: Hamamelis virginiana
Common name: Common Witch Hazel
(Information for this species page was compiled in part by Christina Girdwood in the Spring 2001
Biology 220W course at Penn State New Kensington)
Witch hazel is a large shrub found extensively throughout the eastern and mid-western United States and southern Canada. It is a woody plant with branches six to eight inches in diameter, a smooth, even bark, and a characteristic growth pattern of extensive basal branches that spread laterally into an arching, dome-like form. It can grow twenty to thirty feet tall and so is occasionally referred to as both a large shrub and a small tree. Its leaves are oval shaped,
three to five inches long and one to two inches wide (at maturity) and have wavy
edges and an uneven base.
Witch hazel is most abundantly found in the under-story of well shaded forests with typically low to moderate soil moisture levels. It is very tolerant of wide ranges of both light and moisture and so can also occur in surprisingly dry or sunny habitats. It typically grows in distinct clusters of plants and seldom forms a very broadly or homogeneously distributed community. This clumping of individuals is probably due to the plant's mechanism of seed dispersal (discussed below). Witch hazel's slow, steady rate of growth is only minimally affected by increased light intensities. It does not, then, exhibit the often remarkable acceleration of growth (the "race to the canopy") typically seen in under-story plants in forest light gaps
Flowers, Fruit and Seeds
Witch hazel flowers in the autumn, long after the flowering season has passed for most plants. Its flowers are typically bright yellow, complete, and are potentially self-pollinating. Pollination is usually accomplished, however, by a wide variety of insects. Although pollination occurs in the autumn, fertilization of the ova does not occur until the next May.
Fruit development, then, coincides with the timing of fruit formation seen in most of the
other fruit producing plants of the ecosystem. Seeds develop inside of a woody, two chambered capsule from which they are forcibly ejected at maturity. The ejected seeds typically remain dormant for two years prior to germination. This ejection, which is accompanied by a distinct "snapping" sound, shoots the seeds from twenty to thirty feet away from the parent plant and helps to explain the previously mentioned clustering and clumping of witch hazel plants. This ejection and noise also accounts for another common name of the witch hazel: the snapping hazelnut.
Witch hazel has very few natural enemies. Deer occasionally browse the plant during the winter and gray squirrels may eat the brittle seeds. The food value, though, of the leaves, branches, and seeds
is very low. A weevil (Psuedoanthonomous hamamelids ), though, has evolved a host-specific parasitic symbiosis with witch hazel. The weevil spends the adult portion of its life cycle on the witch hazel shrubs feeding on both leaves and flowers. Fertilized female weevils drill holes into the forming fruit of the plant and lay their eggs inside. The developing larvae, then, consume the fruit and the seeds. These holes in the fruit are visible to the naked eye. This seed parasitism significantly impacts on the ability of the witch hazel to reproduce and spread.
The low, lateral branches of the witch hazel are favored by a number of bird species (including wood thrushes and flycatchers) as nesting sites, but the overall impacts of this shrub on the food and habitat resources of its ecosystem are fairly minimal.
Impact on Humans
Humans in many cultures have utilized the witch hazel plant for a variety of medicinal purposes. The bark and leaves are used to make topical medications for the treatment of cuts, abrasions, hemorrhoids, eczema and other skin conditions. Native Americans also brewed a medicinal tea with its leaves.
Witch hazel has been described as a "docile" plant within its natural communities. Its slow rate of growth and spread, and its minimal contributions to habitat structure and consumer energy flow mark it as a marginal member of the Nature Trail's biota. Its ability, though, to persist under a broad range of environmental conditions, and its slow and steady rate of growth and reproduction ensure both its continued presence and survival within the boundaries of the Nature Trail and also its continued contribution to the biotic diversity and quality of the Nature Trail ecosystem.